RUMOUR ALERT … the Volkswagen Group plans to launch cars that average 300mpg within the next few years. If true, these vehicles could revolutionise the world of motoring. What Volkswagen has so far is the XL1 Super Efficient Vehicle which was seen at the Qatar Motor Show as a concept. This two-door coupé could – and I stress could – be the basis of a forthcoming mass production model. It is powered by a 0.8-litre two-cylinder 48PS diesel engine and a 27PS electric motor. That is 75PS overall, which is enough to propel it to 62mph in 11.9 seconds courtesy of the seven-speed automatic transmission. Top speed is limited to 99mph. This concept's power and performance are therefore comparable to today's, top of the range, Volkswagen High up! city car. That is remarkable for a vehicle which averages 313mpg and boats a carbon emission figure of 24g/km. The new High up!, in contrast, averages 60.1mpg and its emissions are 108g/km.The Volkswagen XL1 Super Efficient Vehicle has numerous innovations that minimise fuel consumption. As such, its bodywork is Carbon Fibre Reinforced Polymer rather than steel. This is very light as reducing mass is key to improving fuel efficiency. It also has lightweight magnesium wheels, ceramic brakes, and aluminium dampers/brake callipers. It therefore only weighs 795KG which is 134KG less than the Volkswagen High up!, and a staggering 410KG lighter than the lowest priced Golf Hatchback. Aerodynamics plays its part too. VW's concept – which has scissor doors mounted to its A posts - therefore lacks wing mirrors and the rear wheels are covered to reduce drag. Furthermore, the vehicle can be powered by its electric motor only for up to 35Km. This – of course – requires no diesel which saves cash and eliminates carbon emissions. However, the traditional diesel engine kicks-in as required. This could be for long trips, hard acceleration, and steep hills. But that is the future. What we have on the market now is the Volkswagen Polo 1.2 BlueMotion. This supermini averages 80.7mpg and returns 91.1mpg on the extra-urban cycle. As such, its carbon emissions are only 91g/km. It even has rock-solid handling, a comfortable ride, and pleasing equipment specification. The Volkswagen Group - which incorporates Audi - also produces the highly efficient Audi A1 1.6 TDI SE. This fashion statement averages 74.3mpg, manages 83.1mpg on the extra-urban cycle, and has emissions of 99g/km. Impressive … but rumours suggest this might be blown out of the water by 2016. Why? Because the Audi 1.0-litre Car is being developed and this four-seater could return 282mpg. Whereas this might sound like science fiction it is inevitable that super-efficient vehicles will hit the mass market. But - I suspect - it will take more years than the rumours suggest. In the mean time, try that Polo. It is fantastic.